Importance

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Abstract

Apparatus and method for molding a plurality of articles having various masses and shapes wherein a parison mass is injected at constant back pressure through a time controlled valve from a supply of molten molding material at predetermined temperature and pressure. The articles are compression molded at predetermined pressures in accordance with their shapes or masses. The variable compression pressures are provided in one embodiment by similar actuators which are unequally excited; and in another embodiment an actuator is coupled to a mold cavity by a machine having a variable mechanical advantage. The actuators are pivotally mounted. A series of lenses including negative powers is particularly contemplated.

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First Claim